A printing plate and a printing plate assembly

Abstract

The utility model discloses a printing plate and printing plate assembly, printing plate (1) includes printing layer (10), and its characterized in that, printing layer (10) is equipped with a plurality of second grid line forming opening (50), the length direction of second grid line forming opening (50) is identical with the length direction of grid line, the bottom surface of printing layer (10) is equipped with a plurality of first grid line containing recess (40), a plurality of first grid line containing recess (40) and a plurality of second grid line forming opening (50) are set up alternately and interval, the length direction of first grid line containing recess (40) is identical with the length direction of second grid line forming opening (50).

Description

Technical Field

[0001] This utility model relates to the field of solar cell technology, specifically to a printing plate and a printing plate assembly. Background Technology

[0002] Back-contact solar cells (BC cells) typically have N-type and P-type sub-grids printed on the back as different electrodes.

[0003] However, the printing order of N-type and P-type subgates is different, which can lead to the problem that the already printed gates affect the morphology of the gates printed later.

[0004] Therefore, how to design and optimize the structure of metal printing plates so that the two types of gates do not interfere with printing and optimize the gate line morphology is an urgent problem to be solved in this field. Utility Model Content

[0005] This utility model aims to solve one of the technical problems in related technologies to a certain extent. To this end, this utility model provides a printing plate and a printing plate assembly.

[0006] To achieve the above objectives, this utility model discloses a printing plate, which includes a printing layer. The printing layer has a plurality of second grid line forming openings, the length direction of which is consistent with the length direction of the grid line. The bottom surface of the printing layer has a plurality of first grid line receiving grooves, which are alternately and spaced from the plurality of first grid line receiving grooves and the plurality of second grid line forming openings. The length direction of the first grid line receiving grooves is consistent with the length direction of the second grid line forming openings. Furthermore, the printed layer includes a metal film and an organic film, the organic film being stacked at the bottom of the metal film, and the first grid line receiving groove being formed on the organic film.

[0007] Furthermore, the width of the first grid line receiving groove is the same as the width of the second grid line forming opening, and the depth of the first grid line receiving groove is less than or equal to the thickness of the organic film.

[0008] Furthermore, the width of the first gate line receiving groove is between 5 μm and 500 μm, the depth of the first gate line receiving groove is between 1 μm and 10 μm, the thickness of the metal film is between 10 μm and 80 μm, and the thickness of the organic film is between 1 μm and 15 μm.

[0009] Furthermore, the metal film has a plurality of metal through holes, and the plurality of metal through holes correspond one-to-one with the second grid line forming opening. At least some of the metal through holes have an opening rate of 100%. The material of the metal film includes iron and iron alloys or nickel and nickel alloys.

[0010] Furthermore, the printing plate also includes an outer frame and a mesh fabric, the mesh fabric being connected between the outer frame and the printing layer, the mesh fabric being arranged around the periphery of the printing layer, and the connection portion between the mesh fabric and the printing layer forming a composite area.

[0011] Furthermore, the connection between the mesh fabric and the printed layer includes adhesive bonding or welding, and the mesh fabric includes metal mesh, nylon mesh, or polyester mesh fabric.

[0012] Furthermore, the spacing between the plurality of first grid line receiving grooves and the adjacent second grid line forming openings is consistent. Furthermore, the width of the second gate line forming opening is between 5 μm and 500 μm. As a second aspect of this application, a printing plate assembly is disclosed, the printing plate assembly including a first printing plate and a second printing plate, the first printing plate having a plurality of first grid line openings spaced apart along a first direction; the second printing plate is the aforementioned printing plate, the first grid line openings matching the first grid line receiving grooves of the second printing plate.

[0013] The printing plate provided in this application is suitable for printing electrodes with complex grid structures, especially for printing electrodes in back-contact solar cells. A first grid line receiving groove is set at the bottom of the printing layer, so that the printing plate can accommodate the grid line electrodes that have been printed in the previous layer in the groove during the printing process, preventing the already formed grid lines from pushing up the printing plate. The groove reduces the surface unevenness, making the printing plate printing smoother. This structure effectively improves the adhesion between the printing plate and the complex three-dimensional substrate without changing the existing printing process, and prevents the paste from spreading, widening or breaking during the printing process. This significantly improves the grid line printing accuracy, extends the service life of the printing plate, optimizes the paste utilization rate, and improves the overall electrical performance and yield of the solar cell.

[0014] These features and advantages of this utility model will be disclosed in detail in the following specific embodiments and accompanying drawings. The preferred embodiments or means of this utility model will be shown in detail in conjunction with the accompanying drawings, but are not intended to limit the technical solutions of this utility model. In addition, each of these features, elements and components appearing in the following text and drawings is multiple and is labeled with different symbols or numbers for convenience, but all represent parts with the same or similar structure or function. Attached Figure Description

[0015] The present invention will be further described below with reference to the accompanying drawings: Figure 1 This is a schematic diagram illustrating one embodiment of the printing plate provided in this application; Figure 2This is a schematic diagram of one embodiment of the electrode structure of a back-contact solar cell; Figure 3 This is a schematic diagram of one embodiment of printing grid lines using the printing plate provided in this application.

[0016] Explanation of reference numerals in the attached figures 1: Printing plate; 2: Outer frame; 3: Mesh fabric; 4: Organic film; 5: Metallic film; 6: Battery cell; 7: Squeegee; 8: Metal paste; 10: Printing layer; 50: Second grid line forming opening; 40: First grid line receiving groove; 100: P-type main grid; 101: P-type secondary grid; 200: N-type main grid; 201: N-type secondary grid. Detailed Implementation

[0017] The embodiments of this utility model are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described are intended to explain this utility model and should not be construed as limiting it.

[0018] The terms "an embodiment," "example," or "example" used in this specification refer to a particular feature, structure, or characteristic described in connection with the embodiment itself that may be included in at least one embodiment disclosed in this application. The phrase "in an embodiment" appearing in various places throughout the specification does not necessarily refer to the same embodiment.

[0019] With the development of photovoltaic technology, back-contact solar cells (BC cells) have gradually become an important direction for high-end photovoltaic modules due to their advantages such as high efficiency, low series resistance, and no front-side shading. The BC cell structure eliminates the front electrode, with all electrodes arranged on the back, reducing shading loss and improving the fill factor and device aesthetics. BC cells typically have both N-type and P-type sub-busbar electrodes printed on the back, arranged in a complementary manner.

[0020] The inventors of this application have discovered that in actual manufacturing processes, electrode printing typically employs a three-step method: first, the main grid electrode is printed and dried; then, the N-type sub-grid is printed; after drying, the P-type sub-grid is finally printed to form a complete back electrode system. In the electrode printing process of BC batteries, because the N-type sub-grid electrode is pre-printed and cured, it forms a micro-protrusion structure on the substrate surface. When printing the P-type sub-grid using traditional screen printing, the pre-printed N-type sub-grid creates a micro-protrusion structure, preventing the screen from fully adhering to the substrate. This leads to ink leakage or diffusion from the edges due to poor adhesion, resulting in abnormal width, misalignment, or even screen breakage of the P-type sub-grid pattern. Furthermore, because the N-row sub-grid protrudes more than the battery substrate surface, it easily contacts the P-type sub-grid printing plate, making it more susceptible to contamination from fine particles carried by the battery, such as silicon dust, coating dust particles, and transmission line impurities. These particles can easily cause localized stress concentration on the printing plate during printing, potentially leading to direct puncture of the organic film. More seriously, in metal printing plates, these impurities can even penetrate the composite structure of the organic and metal films, leading to problems such as damaged pattern openings, ink leakage from the screen, and pattern edge diffusion. This structural damage is often irreversible, severely affecting the lifespan of the screen and printing stability, thereby increasing production costs and reducing yield.

[0021] Some related technologies have attempted to improve the printing accuracy of P-type subgrids by adjusting process parameters such as squeegee angle, reducing screen distance, and controlling paste viscosity, but none of these methods have addressed the problem at its core: the screen structure itself. Therefore, the key challenge remaining to overcome is how to adapt the existing N-type subgrid structure (within the existing protruding structure) to the P-type subgrid printing process while maintaining the strength and graphic accuracy of the screen structure. This would allow for high-precision screen printing of the P-type subgrid, preventing paste diffusion, and simultaneously maintaining printing quality and process compatibility to achieve stable and clear graphic transfer.

[0022] To address the aforementioned problems, as a first aspect of this application, a printing plate 1 is disclosed, such as... Figure 1 and Figure 3 As shown, the printing plate 1 includes a printing layer 10, which has a plurality of second grid line forming openings 50. The length direction of the second grid line forming openings 50 is consistent with the length direction of the grid line. The bottom surface of the printing layer 10 has a plurality of first grid line receiving grooves 40. The multiple grooves and the multiple second grid line forming openings 50 are alternately and spaced apart. The length direction of the first grid line receiving grooves 40 is consistent with the length direction of the second grid line forming openings 50.

[0023] The printing plate 1 provided in this application is suitable for electrode printing with complex grid structures, especially for electrode printing of back-contact solar cells (BC cells). Typically, the front side of a BC cell has no grid lines, and the back side is not simply an N-region or a P-region, but rather has P-regions and N-regions arranged in an interdigitated pattern on the back side. Thus, the anode and cathode of the BC cell are both located on the back side of the cell, and the anode and cathode also have an interdigitated structure arranged according to the corresponding P-regions and N-regions, such as... Figure 2 As shown. Therefore, this application provides a first grid line receiving groove 40 at the bottom of the printed layer 10, so that the grid line electrodes that have been printed in the previous layer can be received in the groove during the printing process of the printing plate 1, so as to avoid the formed grid lines from lifting the printing plate 1 or contaminating the printing plate 1, making the printing plate 1 and the battery cell 6 fit more smoothly, reducing the unevenness of the coating surface of the printing plate 1 by the squeegee 7, so that the coating of the metal paste 8 is smoother and the flow of the paste is smoother, which is conducive to the integrity of the printed grid morphology and prevents the situation of false printing or broken grids due to uneven surface coating.

[0024] The first grid line receiving groove 40 of this application is used to receive the already formed N-type sub-grid 201 during printing on the printing plate 1 and matches the position and size of the N-type sub-grid 201 so that the N-type sub-grid 201 can be completely received in the groove without interfering with the forming of the P-type sub-grid 101. The second grid line forming opening 50 of the printing plate 1 is used to print the P-type grid line.

[0025] The printing plate 1 structure of this application is compatible with the existing three-step printing process and does not require changes to the existing printing process parameters. It effectively improves the adhesion between the printing plate and the complex three-dimensional substrate, prevents the paste from spreading, widening or breaking during the printing process, thereby significantly improving the grid line printing accuracy, extending the service life of the printing plate, optimizing the paste utilization rate, and improving the overall electrical performance and yield of the solar cell.

[0026] This application does not impose any special limitations on the structure of the printed layer 10. It can be a single layer of material or a multi-layer material stacked together. Preferably, the printed layer 10 includes a metal film 5 and an organic film 4. The organic film 4 is stacked at the bottom of the metal film 5. The organic film 4 is generally easy to process. The first grid line receiving groove 40 is formed on the organic film 4. It can be formed by laser grooving, photolithography etching, or thermoforming. Preferably, the groove structure is formed by precision laser processing technology. The depth, width, and position of the groove are precisely aligned with the size and arrangement of the N-type sub-grid to ensure that the printing plate does not lift or the squeegee jumps during the printing of the P-type sub-grid.

[0027] This application does not impose any special limitations on the size of the first grid line receiving groove 40, as long as it can fully accommodate the first grid line, i.e., the N-type sub-grid 201. In some specific embodiments, the organic film 4 expands and deforms more during printing. Therefore, preferably, the width of the first grid line receiving groove 40 cannot exceed the distance between two adjacent second grid line forming openings 50. The organic film 4 needs to provide appropriate space for paste forming and prevent the metal film 5 from directly contacting the battery surface and becoming contaminated. At the same time, the organic film 4 also needs to provide a certain amount of support and resilience so that the printing plate 1 can quickly recover its deformation when the scraping pressure is removed. Preferably, the width of the first grid line receiving groove 40 is the same as the width of the second grid line forming opening 50, and the depth of the first grid line receiving groove 40 is less than or equal to the thickness of the organic film 4.

[0028] The width of the first grid line receiving groove 40 of this application can be consistent with the width of existing battery grid lines. In some embodiments, the width of the first grid line receiving groove 40 is between 5 μm and 500 μm. The depth of the first grid line receiving groove 40 of this application can be adapted to the thickness of the organic film 4. Preferably, the depth of the first grid line receiving groove 40 is between 1 μm and 10 μm, the thickness of the metal film 5 is between 10 μm and 80 μm, and the thickness of the organic film 4 is between 1 μm and 15 μm.

[0029] The metal film 5 has multiple metal through holes, each corresponding one-to-one with a second grid forming opening 50. At least some of the metal through holes have an opening rate of 100%. The material of the metal film 5 includes iron and iron alloys or nickel and nickel alloys. This application does not impose special restrictions on the opening configuration on the metal film 5, as long as it corresponds to the second grid forming opening 50. That is, at least one metal through hole can be provided at the position of the second grid forming opening 50. This can be a single metal through hole with an opening rate of 100%, or it can be a second grid forming opening 50 composed of multiple metal through holes similar in shape to the metal mesh.

[0030] This application does not impose any special limitations on the structure of the printing plate 1. In some specific embodiments, the printing plate 1 further includes an outer frame 2 and a mesh fabric 3. The mesh fabric 3 is connected between the outer frame 2 and the printing layer 10. The mesh fabric 3 is arranged around the periphery of the printing layer 10, and the connection between the mesh fabric 3 and the printing layer 10 forms a composite area. The connection between the mesh fabric 3 and the printing layer 10 includes adhesive bonding or welding. The mesh fabric 3 can be made of metal mesh, nylon mesh, or polyester mesh fabric.

[0031] In general, the P-type sub-grid 101 and N-row sub-grids of the BC battery are uniformly spaced interdigitated electrodes. Preferably, the spacing between the plurality of first grid line receiving grooves 40 and the adjacent second grid line forming openings 50 is consistent. In some embodiments, the width of the second gate line forming opening 50 is between 5 μm and 500 μm. As a second aspect of this application, a printing plate assembly is disclosed, comprising a first printing plate and a second printing plate. The first printing plate is provided with a plurality of first grid line openings arranged at intervals along a first direction. The second printing plate is the aforementioned printing plate, and the first grid line openings match the first grid line receiving grooves of the second printing plate.

[0032] This application does not specifically limit the types of the first and second printing plates. They can be mesh screens made by superimposing metal mesh and patterned organic film layers, or printing plates made by superimposing metal film and organic film layers. The opening of the metal film can be a fully open structure or a semi-open structure with warp and weft connections like mesh.

[0033] In some specific embodiments, the printing plate assembly includes, in addition to the first and second printing plates described above, which are primarily used for printing two types of sub-grid lines with different polarities, a main grid printing plate. The main grid printing plate has openings for P-type and / or N-type main grids for printing lines such as... Figure 2 The P-type main grid 100 and / or N-type main grid 200 shown are preferably printed using a three-step method. First, the P-type main grid 100 and / or N-type main grid 200 are printed. In the second step, an N-type sub-grid 201 is formed by printing with a first printing plate. The N-type sub-grid 201 is connected to the N-type main grid 200. In the third step, a P-type sub-grid 101 is printed with a second printing plate. The P-type sub-grid 101 is connected to the P-type main grid 100. The P-type sub-grid 101 and the N-type sub-grid 201 form an "interdigitated" electrode structure. Because the second printing plate is provided with a first grid line receiving groove, when the second printing plate is printing close to the surface of the battery cell in the third step, the groove on the printing plate will accommodate the N-type sub-grid formed in the second step. This makes the second printing plate adhere more evenly to the battery cell and prevents the N-type sub-grid from being partially lifted up to form a height difference. As a result, the metal paste is scraped more smoothly and the paste flows more smoothly, which is beneficial to the integrity of the P-type sub-grid morphology.

[0034] The printing component of this application maintains high-resolution printing capabilities while improving the adhesion between the printing plate and the three-dimensional structural substrate. The flow is controlled during the printing process, the edges of the P-type sub-grid pattern are clear and the widening error is small, which significantly improves the accuracy and consistency of the pattern.

[0035] The above are merely specific embodiments of this utility model, but the scope of protection of this utility model is not limited thereto. Those skilled in the art should understand that this utility model includes, but is not limited to, the contents described in the accompanying drawings and the specific embodiments above. Any modifications that do not depart from the functional and structural principles of this utility model will be included within the scope of the claims.

Claims

1. A printing plate, said printing plate (1) comprising a printing layer (10), characterized in that, The printed layer (10) has a plurality of second grid line forming openings (50), the length direction of the second grid line forming openings (50) is consistent with the length direction of the grid line, and the bottom surface of the printed layer (10) has a plurality of first grid line receiving grooves (40), the plurality of first grid line receiving grooves (40) and the plurality of second grid line forming openings (50) are alternately and spaced apart, the length direction of the first grid line receiving grooves (40) is consistent with the length direction of the second grid line forming openings (50).

2. The printing plate according to claim 1, characterized in that, The printed layer (10) includes a metal film (5) and an organic film (4), the organic film (4) being stacked at the bottom of the metal film (5), and the first grid line receiving groove (40) being formed on the organic film (4).

3. The printing plate according to claim 2, characterized in that, The width of the first grid line receiving groove (40) is the same as the width of the second grid line forming opening (50), and the depth of the first grid line receiving groove (40) is less than or equal to the thickness of the organic film (4).

4. The printing plate according to claim 3, characterized in that, The width of the first gate line receiving groove is between 5 μm and 500 μm, the depth of the first gate line receiving groove is between 1 μm and 10 μm, the thickness of the metal film is between 10 μm and 80 μm, and the thickness of the organic film is between 1 μm and 15 μm.

5. The printing plate according to claim 2, characterized in that, The metal film has multiple metal through holes, and each of the multiple metal through holes corresponds one-to-one with the second grid line forming opening. At least some of the metal through holes have an opening rate of 100%. The material of the metal film (5) includes iron and iron alloys or nickel and nickel alloys.

6. The printing plate according to claim 1, characterized in that, The printing plate also includes an outer frame (2) and a mesh (3). The mesh (3) is connected between the outer frame (2) and the printing layer (10). The mesh (3) is arranged around the periphery of the printing layer (10), and the connection between the mesh (3) and the printing layer forms a composite area (35).

7. The printing plate according to claim 6, characterized in that, The connection between the mesh fabric (3) and the printed layer (10) includes adhesive bonding or welding, and the mesh fabric (3) includes metal mesh, nylon mesh or polyester mesh.

8. The printing plate according to any one of claims 1 to 7, characterized in that, The spacing between the plurality of first grid line receiving grooves (40) and the adjacent second grid line forming openings (50) is consistent.

9. The printing plate according to any one of claims 1 to 7, characterized in that, The width of the second gate line forming opening is between 5 μm and 500 μm.

10. A printing plate assembly, characterized in that, The printing plate assembly includes a first printing plate and a second printing plate, wherein the first printing plate is provided with a plurality of first grid line openings arranged at intervals along a first direction; The second printing plate is the printing plate according to any one of claims 1 to 9, wherein the first grid line opening matches the first grid line receiving groove (40) of the second printing plate.

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